• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Where to buy replacement outputs

Vistance

Vistance

Super Member
I need some help finding a place to buy replacement outputs. I have a receiver which just had a channel kick the bucket so I need to find an ECG 247 and ECG 248 TO3 output. I can find websites with info on this all day, but no one is selling anything and the few that are seem very shady and unreliable. I'd like to know a reliable site to buy outputs from (even if they don't have this one in stock, as I'd like to start keeping a list of reliable vendors).

Hm, on second thought I do need to know explicitly where I can buy these Sylvania ECG 247 and 248 outputs or a cross-referenced equivalent.
 
Last edited:
Register to hide this ad
Onsemi's is my first choice . NTE/ECG don't even get and honorable mention..
Mouser or Digikey for Onsemi and Fairchild.Sometimes I buy direct from Onsemi.
 
Last edited:
Is the receiver make and model a secret?

The ECG outputs are themselves substitutes no doubt someone made at some point in the past. Forget about them and let's find out what the original outputs were and an appropriate substitute can then be made.
 
It was to my knowledge not important what model the amp was, but simply the outputs. We're talking about a Sherwood S-7900A here.
 
Vistance said:
It was to my knowledge not important what model the amp was, but simply the outputs. We're talking about a Sherwood S-7900A here.
Click to expand...

Overload and I .Were trying to identify what the original outputs are suppose to be..Those ECG's are not original!!! And may not even be a suitable substitute for the original output transistors.
 
Do you have a service manual or a schematic diagram ?
 
Oh? I had no idea. Sylvania seemed like the appropriate outputs given it was an American made receiver. I appreciate the help guys, I just want to get this one back up and running again. It has always run rather hot, but never gave any problems until the other day - smoke rolled out of it from the left channel amp board (I checked and nothing is blown internally - but upon removing outputs, the problem ceases to exist).

I'll scour the web for the 7900A service manual, go figure I have the SM for many other things that I never ended up needing but not this one. Pete, thanks for the link - that looks like the 8800 which looks quite a bit older than mine. Old enough that it uses musical watts and such, my Sherwood was supposed to be rated at 60 watts per channel IIRC. Outlook is not good for this service manual...ugh, this is probably why whoever put these outputs in chose them - because he couldn't figure out the originals. What am I going to do if I can't figure out the suitable outputs for this? I'd hate to have to scrap a formerly fine working receiver on the count of a blown output. It would be a downright shame, this sounded pretty good though a bit too warm and boomy - but maybe now that's because of the non-original outputs.
 
Last edited:
You can purchase the NTE equivalents at Parts Express a good cross for the 247 is A 2N6057 and a good SK equivalent for the 248 is SK3949. You may want to try AG Tannenbaum for a schematic to find what was originally used. The transistors you have are Darlingtons

Good Luck
 
just checked the manual i linked to and all outputs are npn . so either the amp is different or yours has the wrong transistors installed
 
Boy this is getting messy. So do I replace the outputs with equivalents, or risk putting in other outputs which could do more damage if they're not properly matched? I checked the other channel of outputs and they're all a matched set of Sylvania outputs. Whoever hodge podged these in there at least was consistent and didn't just do one side, which I kind of find surprising since I know most people in these cases just replace the bad channel's outputs and leave the others alone. I wish they had, this wouldn't have complicated matters so much.
 
I believe the receiver was probably repaired and functioning with those transistors. But a $15 investment for a schematic will be your insurance for a successful repair
 
DRKNIFE had posted here a while back with pics of his 7900A. Try contacting him to see still has it and can remove the transistor covers to let you know what are in his receiver.
 
The originals were Motorola SJ1902 and 1903 Darlingtons. I would think that ON Semi 2N6284 and 6287 should get the job done.
 
I would agree with overload, the 2n6284/87 has higher current specs. These will do just fine.
 
That On Semi place is about the most non-understandable website I've ever seen. Feels like it was made for robots to read or something! Is there somewhere else that sells these outputs that is actually understandable so I don't feel like I'm ordering robot parts? I bought some darlington power packs from I believe a place called MCM Electronics before and it was nice because they actually had pictures of what they looked like. I have a local place that might have these - but what do I need to tell them I want to order and in what quantities? For the Motorola and Darlington outputs, did it have two of each? Seems strange, all the amps I've taken apart always had the same branded output throughout.

Edit: Ah, ok I found them at Mouser - they're understandable actually. So if my local electronic part supplier would have these would I tell them I'm looking for Darlington 2N6284/87 outputs? I'd just like to know what to ask for from them, it may be cheaper/easier to buy them local but Mouser seems reasonable on the price as long as they don't have some "minimum $50 order" or something.
 
Last edited:
You can always go to Parts express as they have the NTE equivalents for just over $6 each and you know they are a direct cross now.

No Muss No Fuss
 
just a thought your darlingtons wont test like a regular transistor . so unless obviously shorted you might have a different problem . drivers will be suspect in any case .
 
I'm pretty sure it's the outputs, like I said when I remove the left channel's output pair the receiver stops getting very hot and smoking. I sent Drknife a message, hoping he has a picture of the back to help me out. I know hooking outputs in backwards can basically toast an amp/the outputs so I'd like to make sure of how they'd be mounted. Would the higher number replace my higher number and lower replace the lower?
 
Petehall is correct darlingtons will not show a typical reading on your multimeter.

The 2n6284 is a npn transistor which is what the original sj1902 was and the 2n6287 a pnp as for the sj1903
 
You must log in or register to reply here.
Back
Top Bottom